Alko 8" Jockey Wheel - has a standard clamp with a rubber tyre (200mm diameter) & steel rim.

Jockey Wheel,200mm (8”) with clamp, Zinc.
Specifications
Wheel Size (D): 150mm dia.
Mounting: Clamp
Static Capacity: 400 kg
Tube O.D.: 48mm
Closed H1: 567mm
Open H2: 832mm
Closed G1: 262mm
Open G2: 522mm
L1: 182mm
Weight: 7 kg